In next generation multimedia mobile communication systems, which have been actively studied in recent years, there is a demand for a system capable of processing and transmitting a variety of information (e.g., video and radio data) in addition to providing the early-stage voice service.
Orthogonal frequency division multiplexing (OFDM) is a multiple-subcarrier modulation scheme in which data transmission is achieved by dividing a frequency band into a plurality of orthogonal subcarriers. The OFDM is one of noticeable core technologies in the next generation multimedia mobile communication systems. Orthogonal frequency division multiple access (OFDMA) provides multi-user multiplexing by combining the OFDM with frequency division multiple access (FDMA) or time division multiple access (TDMA) or code division multiple access (CDMA).
Additional physical channels exist to transmit uplink data in an OFDMA-based communication system. A fast feedback channel is a physical channel for transmitting uplink control information. A method for allocating partial usage of subchannels (PUSC) resources is used in the fast feedback channel. The control information transmitted through the fast feedback channel is various, such as, channel quality information (CQI) indicating a channel condition, precoding matrix information (PMI) of a multiple antenna system, rank information (RI), etc. The control information is transmitted periodically or occasionally for smooth communication between a base station and a user equipment.
In general, not many resources on a frequency-time axis are allocated to the fast feedback channel for transmitting the uplink control information. When information is transmitted with a limited radio resource, accuracy of the uplink control information is not guaranteed, and an expressible codeword is limited, which leads to insufficient operational flexibility. Moreover, when a user has to transmit a plurality of pieces of uplink control information through the fast feedback channel, a plurality of subchannels are allocated, resulting in increase of overheads.
Accordingly, there is a need for a method for transmitting a plurality of pieces of uplink data on one subchannel while increasing a size of data transmitted on one uplink subchannel.